Meaning: This sentence is a personification that means the painting is telling a sad story.
Choice of Words: Canvas is the cloth that artists paint on. Weeps means to cry. Teardrop is a drop of water that comes from the eye when someone cries. Tale is a story. When we put it all together, it means that the painting is telling a sad story, and the tears in the painting are like the tears that someone sheds when they are crying.